The merger is expected to have an effect on the domestic retail trade of the DIY market, the Commission for the Protection of Competition (CPC) said in a statement published on its website.
While the companies, part of Rodna Zamya Holding, provide real estate rental services and natural gas trading, the companies related to one of the investors, Peyo Nikolov, are focused on operating DIY retail stores.
The value of the deal was not disclosed.
The competition regulator gave its approval to Haedus to take full control over bauMax Bulgaria, part of troubled Austrian group bauMax at the time.
Sofia-based Haedus was set up in June 2013.